If a general counsel decided to drop a set number or percentage of the law firms used that were paid more than a de minimis amount, that would encourage better evaluations of firms. In-house lawyers would also more credibly tell the firms they use that the firms must stay on their toes.

Forced-ranking and lopping off the lowest few might also lead to some gaming if lawyers retain a firm only to drop them. The compromise might be for a general counsel to unleash this effort every few years, to clear out the undergrowth.